He represented Annapolis West in the Nova Scotia House of Assembly from 1978 to 1993 as a Progressive Conservative member. Kerr served in the Executive Council of Nova Scotia as Minister of Culture, Recreation and Fitness from 1980 to 1981, as Minister of the Environment from 1981 to 1983, as Minister of Finance from 1983 to 1993, as Minister of Housing from 1988 to 1989 and as Minister of Tourism and Culture from 1992 to 1993. Kerr was defeated when he ran for re-election in the 1993 election.[1] He was an unsuccessful candidate for a seat in the House of Commons in 2006.

Kerr married his high-school girlfriend, Marica Longmire in 1970. They live in Granville Centre, Nova Scotia and own a beef farm and logging operation. The couple have two children, Gillian and Megan. He is an active warden in the Anglican Church.